When cans became popular for containing beverages openers were needed; subsequently opening tabs were provided in the can-ends and the removable ring-pull tab became very popular. The ring-pull tab evolved into the non-removable stay-tab and hinged non-removable push-down gates to solve the problems of ring-pull tab litter and exposed sharp can opening edges. Exemplary of hinged push-down gates is the triple-fold gate disclosed in U.S. Pat. No. 3,334,795 and U.S. Pat. No. 4,215,792. The basic purpose of these two patents was to provide a one-piece easy-open hinged can top without the need for opening attachments like tabs, levers, and cams. Other types of gated can-ends are also available and the general basic construction of any gated can-end is to provide a gate which is slightly larger than and underlies an opening or aperture in the can-end. The gate, hinged to the can-end at an edge portion of the opening, remains attached to the end when pushed downward into the can to open it.
Prior technology can-ends do not address the problems with spilling, contamination, and gas charge preservation in an economically manufacturable and/or practicable design. Either too much energy and time is needed to form the material, too much material is required to manufacture the can-end, or the can-end design interferes with efficient recyclables, standard packaging, vending machine dimensions, and stackability; or requires the user to hand-operate a device to reseal and reopen the can opening between each sip, if immanently in danger of being contaminated by insects, sand, rain, soap, or other contaminants. The current flip-top is also difficult to open without breaking long fingernails and difficult for young children to open.